Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!sdd.hp.com!decwrl!sgi!shinobu!odin!odin.corp.sgi.com!portuesi From: portuesi@tweezers.esd.sgi.com (Michael Portuesi) Newsgroups: comp.sys.ibm.pc.misc Subject: Re: Extended and Expanded memory Message-ID: Date: 20 Aug 90 11:55:12 GMT References: <26045@bellcore.bellcore.com> <1990Aug18.110404.28864@cbnewsl.att.com> Sender: news@odin.corp.sgi.com (Net News) Reply-To: portuesi@sgi.com (Michael Portuesi) Distribution: usa Organization: Silicon Graphics, Inc., Mtn. View, CA Lines: 43 In-Reply-To: rl@cbnewsl.att.com's message of 18 Aug 90 11:04:04 GMT >>>>> On 18 Aug 90 11:04:04 GMT, rl@cbnewsl.att.com (roger.h.levy) said: > In article <26045@bellcore.bellcore.com>, wind@rruxi.bae.bellcore.com (Wind Chen) writes: >> LIM 3.2 and LIM 4.0 are two different thing, they are not compatible. >> To use LIM 4.0, you will need hardware support, if you EMS board didn't say it >> supports LIM 4.0, chances are, it does NOT support. > Yes they are different but most of the rest is untrue. From the Waite Group's > MSDOS Developer's Guide: > The user does not have to buy any new hardware to use applications > that are written to the LIM EMS 4.0 specification. Older expanded > memory boards designed for the LIM EMS 3.2 specification can > support the 4.0 specification - the manufacturer just has to write > a new EMM to implement the 4.0 function calls. > Established manufacturers such as AST do just this sort of thing. Also, the > LIM 3.2 function calls exist in LIM 4.0 but 4.0 has more of them. I would > call that "upward compatible" rather than "not compatible." Okay, my question is: Is LIM-EMS 4.0 implemented in software on 3.2 hardware equivalent to LIM-EMS 4.0 on 4.0 hardware in both features and performance? The reason why I ask this is that I am currently running DESQview 2.26 on my Toshiba T1000XE laptop computer. It has an 80C86 and 2.4 MB of EMS memory. The Toshiba docs say that the hardware is 3.2, and that the EMS driver supports LIM-EMS 4.0. But DESQview certainly isn't behaving like there is EMS 4.0 in the machine (yes, I am using XDV). I understand that a big difference between 3.2 and 4.0 is that 4.0 provides a much greater range of places where the expanded memory can be mapped into conventional memory. How is this done in software for 3.2 boards? By copying data all over the place? Yuck. --M -- __ \/ Michael Portuesi Silicon Graphics, Inc. portuesi@sgi.com "man, this is weak."